Karma - 7:00 pm on Aug 21, 2011 (gmt 0)
The keyword in the URL isn't the main objective, but I think it would make more sense for the visitor.
There are also potential downsides to implementing sitewide redirects... roughly a 15% loss in PR to redirected pages, and lots of places to mess up.
Are there any common things that people mess up? Would doing the redirects section by section be safer?